278 PRACTICAL ORGANIC CHEMISTRY
Acetanilide, Bromacetanilide.--Primary and second-
ary bases form -acetyl derivatives with acetic acid, acetyl
chloride, or acetic anhydride (see Reactions, pp. 76, 77)-
Tertiary bases are unacted on in this way. As the acetyl
derivatives are much less volatile than the original bases, the
method is frequently used for separating a tertiary base from
mixtures containing the other two (see Prep. 59, p, 156). The
anilides are very stable compounds ; they can be distilled, as a.
rule, without decomposition, and may be directly brominatecl,
chlorinated and nitrated. In these reactions, either the ortho-
or para- or both derivatives are formed. The remaining
hydrogen atom of the amino-group may be replaced by ( 0 a
second acid radical, by the action of acetic anhydride, (2)
sodium, by the action of the metal, (3) a nitroso-group, with
nitrous acid, and (4) chlorine or bromine, by the action of hypo-
chlorous or hypobromous acid.
CfiH5N(CO. CH,).2 Diacetanilide.
QjHsNNa. CO. Clio, Sodium acetanilide.
C(5H5NC1. CO.CH3 Acetchloranilide.
The mechanism of the change effected in producing substitu-
tion products by halogens appears to occur in two steps, the first
being the addition of a molecule of halogen, probably to the
nitrogen, the second being an isomeric change accompanied (if
water is present) by the elimination of halogen acid.
CflI-I5.NH.CaI-I3O 4- Br2 = C(;H5NILC2H,O
CGH;,NHBr.,.C2ILO = CGn4BrNH.CoIl>O.IIBr.
All the anilides are hydrolysed by strong mineral acids or
alkalis and the acid radical removed (see also Beckniann's
reaction, Prep. loo, p. 212).
Formanilideis ^.taittomeric compound, z>., it reacts as though
it possessed the alternative formula:,
for it yields two isomeric ethers, the one,'by the action of
methyl iodide on the silver salt, and the other by the action of
methyl iodide on the sodium compound (Comstock). Acet-